1. Field of the Invention
This invention relates generally to food processing and to the refining of crystalline saccharides such as sugar, and more particularly it relates to the refining of crystalline saccharides in a process for making confections such as dark and milk chocolate, and ingredients therefor.
2. Brief Description of the Prior Art
Food products made from ingredients including a saccharide such as sucrose and an edible oil or fat such as cocoa butter are well known. An important group of these food products is comprised of confections, including candy.
Dark chocolate is a well known confection prepared from chocolate liquor, sugar and cocoa butter, and may include other ingredients. Milk chocolate is a chocolate which includes milk or milk solids as well. As used herein "chocolate" denotes both dark and milk chocolate. The process of making chocolate is reviewed generally in B. L. Zoumas and E. J. Finnegan, "Chocolate and Cocoa", Kirk-Othmer Encyclopedia of Chemical Technology, Vol. 6 (3rd Ed., Wiley-Interscience New York) 1-19.
As a confection, chocolate can take the form of solid pieces of chocolate, such as bars, and can also be incorporated as a component of other, more complex confections that are typically hollow items formed from chocolate, or confections which include chocolate as a coating upon a center ingredient of the confection, such as caramel, fruit pieces, nuts or the like.
The process of coating chocolate onto a confection is known as enrobing the piece. Enrobing is accomplished when the chocolate is in a fluid state, and a proper viscosity must be maintained in order to produce a satisfactory coated product.
Finished chocolate is a suspension of very fine particles (usually less than 50 micrometers) in fat. The particles consist of cocoa solids and crystalline sucrose as well as milk solids in the case of milk chocolate. Because of their prior processing, the cocoa solids are generally already fine enough before incorporation into the milk chocolate mixture. Milk solids require little size reduction. Sucrose, however, requires considerable size reduction, since extra fine grade sucrose, for example, typically varies in crystal size from about 400 micrometers to about one millimeter, with the greatest frequency of size occurring at about 750 micrometers. To satisfactorily function as an ingredient in chocolate, therefore, these sucrose crystals must be reduced in size to less than about 50 micrometers. Similar considerations apply in the processing of other types of confections.
It is known that the viscosity of chocolate increases in direct proportion to the amount of water present in the paste. This factor is normally controlled by eliminating water from the chocolate. Moreover, it is known that at least about fifty percent of the surface area of particles in milk chocolate is produced by the presence of particles below two micrometers in size. The presence of these ultrafine particles increases viscosity, and increasing amounts of cocoa butter (fat) are required to coat such particles in order for the chocolate to flow properly in manufacturing operations.
Processes for producing dark or milk chocolate can be either "wet," in which process condensed milk is employed, or "dry," in which process milk powder is used. In one "wet" process for making milk chocolate given in Bernard W. Minifie, Chocolate, Cocoa and Confectionery: Science and Technology, (The AVI Publishing Co., Inc., Conn., pp. 90-94, the following steps are carried out:
(1) Raw milk is filtered, cooled to about 40.degree. F. and stored in large insulated stainless steel tanks. PA1 (2) The milk is preheated to about 75.degree. C. (165.degree. F.) and concentrated to about 30-40% total solids by weight in a continuous evaporator. PA1 (3) The total solids content of the milk is measured and sucrose is added to form a sugar/milk mixture. The mixture is transferred to vacuum pans. Condensation under vacuum at about 75.degree. C. (165.degree. F.) is permitted to occur until a total solids content of about 90% by weight is attained. Some sugar crystallization may begin to occur. PA1 (4) Cocoa liquor is charged to a heavy duty mixer (e.g., a melangeur) and the condensed sugar/milk mixture is added gradually with mixing. The contents of the mixer are kneaded for 20-30 minutes giving a stiff paste. Crystallization of the sucrose continues to occur during kneading; PA1 (5) The paste is placed in shallow trays and dried in a vacuum oven at about 75.degree. C.-105.degree. C. for 4-8 hours, depending on the heat transfer fluid (steam or hot water) used, to give a crumb. PA1 (6) The crumb is mixed in a kneader with cocoa butter to give a coarse paste. PA1 (7) The paste is "refined" (ground) by passing the coarse paste from the kneader through the nips of pairs of steel rollers to give a drier, powdery material. Refining mechanically breaks up crystalline sugar particles, fibrous cocoa matter, and milk solids. The paste is repeatedly passed through the refiner until a target particle size range is obtained (for fine chocolates, about 20-30 micrometers). PA1 (8) The refined paste is mixed with flavoring materials such as vanillin, and cocoa butter is added to adjust viscosity, and an emulsifier such as lecithin may be added. PA1 (9) The refined paste is "conched," that is, slowly kneaded or mixed at a temperature of from about 45.degree.-55.degree. C., to permit moisture and volatile acids to escape. PA1 A. Extra fine grade granulated sucrose, cocoa butter, chocolate liquor, and spray dried whole milk powder are combined and mixed. PA1 B. The mixture from step (A) is passed repeatedly through the nips of a plurality of highly polished refining rolls, such that the sizes of the particles, especially the sucrose, are significantly reduced. PA1 C. Step (B) can be repeated with finer roll settings such that particles smaller than 50 micrometers are produced. PA1 D. The mixture is then stirred while heating to give the final desired consistency to the milk chocolate.
In view of the complexity of the just described wet process for making milk chocolate, a less complex dry process has been developed comprising the following steps:
The just described process of steps A-D is obviously less complex than the former wet process, however it has been found that the particle distributions of the two processes differ, thereby producing milk chocolate having diverse flow characteristics. In the process embodying the step of dissolving sucrose in fresh whole milk, the sucrose is eventually recrystallized to a particle size range from about 10 micrometers to about 25 micrometers. In the process employing whole milk powder instead of fresh whole milk, there is obviously an absence of water to dissolve the sucrose crystals. Therefore, in passing through the refining rolls set to produce particles smaller than 50 micrometers, the sucrose crystals must first be reduced in size from an initial size of up to one millimeter to less than 50 micrometers. In fact, by using the technique of scanning electron microscopy (SEM), it has been found that such crushing of sucrose crystals produces many ultrafine crystals having a particle size below two micrometers, and that the particle count in such a process increases exponentially as the particle size decreases linearly. Moreover, sucrose particles that have been crushed look very much like broken glass, being irregular and having jagged edges, while sucrose crystals which have been dissolved in whole milk and recrystallized have the appearance of glass that has been fire polished. These two prior processes of producing milk chocolate are known to produce chocolate having different viscosity characteristics.
It is an object of this invention to provide a process for making food products including both at least one saccharide and at least one edible oil or fat that is both economical and which enables the viscosity characteristics of the product to be readily controlled. In the case of milk chocolate, the invention enables the more economical and modern dry process to produce product which, like the wet process, is rheologically more desirable than obtained in the dry process described above. In the case of dark chocolate, the invention enables this traditionally dry process to produce product with more desirable rheological characteristics.
It is an object of this invention to provide processes for preparing food products, such as confections, which comprise an improved manner of controlling saccharide crystal particle size distribution.
It is an object of this invention to provide milk and dark chocolates in which the fat content is reduced compared to the classical whole milk powder and classical dark chocolate processes.